Lars Strong from Upsite Technologies has provided this blog post about the evolution of bypass airflow as an educational resource for curious readers. Check it out below:
The Uptime Institute published the first paper on bypass airflow over 10 years ago. That research, conducted by engineers from both the Uptime Institute and Upsite Technologies, quantified the ratio of bypass openings to intentional openings, such as perforated tiles, in raised floors. The concept of bypass airflow was developed with a focus on unmanaged openings in the raised floor. While unmanaged openings release bypass air, they are not the cause of bypass airflow.
The definition of bypass airflow is any conditioned air supplied by a cooling unit that does not pass through IT equipment before returning to a cooling unit. In addition, air that passes through IT equipment multiple times is defined as IT equipment exhaust air circulation. The ideal for airflow in a computer room is for every molecule of conditioned air supplied by cooling units to pass through IT equipment just once before returning to a cooling unit. Any volume of air delivered by cooling units that is greater than the volume of air consumed by IT equipment becomes bypass airflow.
The original Uptime Institute research revealed that on average 60% of computer room cooling capacity was escaping through unsealed cable openings and misplaced perforated tiles. Recent research by Upsite Technologies of 45 computer rooms reveals that on average 48% of conditioned air is escaping from unsealed openings and misplaced perforated tiles. These statistics indicate surprisingly poor improvements in airflow management over the last decade. It is also clear that there is a need for a broader understanding of airflow management fundamentals. For example, many of the sites in Upsite’s research had installed either hot or cold aisle containment without completing management of the raised floor bypass open area.
Contact your local Accu-Tech Representative to learn more about Upsite Technologies, or visit their vendor page here.